The agencies involved in search operation in Beas river on Sunday used world’s advance marine technology side-scan sonars and LIDAR — a Rs 10 crore remote sensing device — without any success in tracing the bodies of missing engineering students from Hyderabad.

So far, only eight bodies have been recovered from the river. The bodies of remaining 16 students and a tour operator remained elusive even as the search operation entered eighth day.

The side-scan sonars, usually used in the sea for conducting surveys and sampling of the under-water surface by Navy and other agencies, were deployed for the first time in the country in a search operation. Beside the hi-tech sonars, NDRF also used LIDAR (Light Detection and Ranging) — a remote sensing technology used in hydrological surveys for measuring distance by illuminating a target with a laser and analysing the reflected light.

The Sunday operation started at around 7 am under supervision of M Subramanian, a senior Navy commander, whose team of marine experts and divers first installed the side-scan sonars on a boat and then carried an extensive search of the Pandoh dam, besides Beas river. Rafts with NDRF, ITBP and Army divers were kept stand by for the search on basis of data collected with computer-backed system.

“Side-scan sonar uses sound waves to find and identify objects in the water. It transmits sound energy and analyses the return signal (echo) that bounces back from the other objects under the water. But, if the object or the body is buried under sand and silt — which is the case in Pandoh — the system has its limitations,” the Navy commander said.

Mandi Deputy Commissioner Devesh Kumar, while talking to The Indian Express, said, “I had some expectations from the two new devices to at least provide clues about the location of the bodies. We are really running out of options as both manual as well as technological innovations have not helped. Only thing left is to wait for a few more days if the bodies come up on the water surface as a natural process. Parents are more or less convinced on this suggestion.”

On Saturday, a three-km long stretch of Beas river was drained dry to enable nearly 500 personnel of NDRF, Navy divers, Army, SSB and a team of Andhra Pradesh divers to search the missing bodies close to the site of the tragedy at Thalout.

Telangana Minister for Home Naini Narsimha Rao, who is camping at the site, admitted that the parents are not in favour of flushing out of water from Pandoh dam for the search as such an exercise will mutilate the bodies.

Last Sunday, 24 students from a private college in Hyderabad and a co-tour operator Parahlad were washed away when continued…